<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        // 常量与变量就不用说了 就写写修改对象吧
        const arr = [1, 2, 3];
        arr.push(4);
        console.log(arr);
        
        const obj = {
            age: 12,
            name: 'lisi'
        }
        obj.age = 20;
        obj.id = 1;
        console.log(obj);
        
    </script>
</body>
</html>